/**
 * libpsd - Photoshop file formats (*.psd) decode library
 * Copyright (C) 2004-2007 Graphest Software.
 *
 * libpsd is the legal property of its developers, whose names are too numerous
 * to list here.  Please refer to the COPYRIGHT file distributed with this
 * source distribution.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * $Id: psd_zip.c, created by Patrick in 2007.02.02, libpsd@graphest.com Exp $
 */

#include "libpsd.h"
#include "psd_config.h"

#ifdef PSD_INCLUDE_ZLIB
#include <zlib.h>
#include <memory.h>

psd_status psd_unzip_without_prediction(psd_uchar *src_buf, psd_int src_len, 
    psd_uchar *dst_buf, psd_int dst_len)
{
    z_stream stream;
    psd_int state;

    memset(&stream, 0, sizeof(z_stream));
    stream.data_type = Z_BINARY;

    stream.next_in = (Bytef *)src_buf;
    stream.avail_in = src_len;
    stream.next_out = (Bytef *)dst_buf;
    stream.avail_out = dst_len;

    if(inflateInit(&stream) != Z_OK)
        return psd_status_unzip_error;
    
    do {
        state = inflate(&stream, Z_PARTIAL_FLUSH);
        if(state == Z_STREAM_END)
            break;
        if(state == Z_DATA_ERROR || state != Z_OK)
            break;
    }  while (stream.avail_out > 0);

    if (state != Z_STREAM_END && state != Z_OK)
        return psd_status_unzip_error;

    return psd_status_done;
}

static
#ifdef __GNUC__
__inline
#else
#ifdef __cplusplus
inline
#endif
#endif
psd_bool psd_test_big_endian(void)
{
    static psd_bool result = 2;
    const psd_int byte_order[1] = { 1 };

    if (result == 2)
    {
        if(((char *)byte_order)[0] == 1)
            result = psd_false;
        else
            result = psd_true;
    }

    return result;
}

psd_status psd_unzip_with_prediction(psd_uchar *src_buf, psd_int src_len, 
    psd_uchar *dst_buf, psd_int dst_len, 
    psd_int row_size, psd_int color_depth)
{
    psd_status status;
    psd_bool big_endian;
    int len;
    psd_uchar * buf;
    psd_ushort * wbuf;

    status = psd_unzip_without_prediction(src_buf, src_len, dst_buf, dst_len);
    if(status != psd_status_done)
        return status;

    big_endian = psd_test_big_endian();
    
    buf = dst_buf;
    wbuf = (psd_ushort *)dst_buf;
    do {
        len = row_size;
        if (color_depth == 16)
        {
            if (big_endian == psd_true)
            {
                while(--len)
                {
                    *(wbuf + 1) += *wbuf;
                    wbuf ++;
                }
                wbuf ++;
            }
            else
            {
                while(--len)
                {
                    *(buf + 2) += *buf + ((*(buf + 1) + *(buf + 3)) >> 8);
                    *(buf + 3) += *(buf + 1);
                    buf += 2;
                }
                buf += 2;
            }
            dst_len -= row_size * 2;
        }
        else
        {
            while(--len)
            {
                *(buf + 1) += *buf;
                buf ++;
            }
            buf ++;
            dst_len -= row_size;
        }
    } while(dst_len > 0);

    return psd_status_done;
}

#endif // ifdef PSD_INCLUDE_ZLIB
